Charles e



(No Model.)

C. E. SGRIBNER. TELEPHONE SWITGHBOARD APPARATUS.

Patented Jan.. 29, 1895.

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CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE l/VESTERN ELECTRIC COMPANY, OF SAME PLACE.

TELEPHONE-SWITCHBOARD APPARATUS.

SPECIFICATION forming part of Letters Patent No. 533,147, dated January 29, 1895. Application tiled May 13,1892. Serial No. 432,899. (No model.)

To a/Z wir/0m it may concer/'m Be it known that I, CHARLEs E. SORIBNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephone-Switchboard Apparatus, (Case No. 300,) of which the following is a full,clear, concise, and exact description, reference being had to the accompany- Io ing drawings, forming a part of this specification.

My invention relates to the operators connecting apparatus or outfit of telephone switch boards.

i5 The object of the invention is to simplify the construction and manipulation ofthe connccting outfit.

Heretofore it has been customary to provide pairs of loop plugs for the operator of 2o the switch board, the dilferent members of a pair being connected together through ilexible conductors, and keys in connection with each pair of connecting plugs and cords, ar-

ranged to disconnect either plug from the other and to connect it to a source of electricity to send calling signals, and other keys to connect the operators telephone apparatus with the cord circuit.

My invention is designed to dispense with 3o the various keys of the connecting outfit, thus effecting a saving in the expense of the apparatus, and at the same time facilitating the establishment of connection between two telephone lines by reducing the number of op- 3 5 erations or motions required in establishing such connection.

In my invention I employ spring jacks and connecting plugs adapted for insertion into them of construction essentially similar 4o to those heretofore employed. In addition to the usual contact pieces of the connecting plug, however, I provide a short sleeve or contact piece upon the plug adapted to make contact with the line spring of the spring jack when the plug is fully inserted into the jack, but normally held out of contact with the line spring while the plug is in the spring jack, the tip of the plug being of such form that the pressure of the line spring thereupon pre- 5o vents the insertion of the plug entirely into the jack excepting by an additional effort. This additional contact piece is connected with a calling generator or other source of electric current appropriate to operate the signal apparatus at the substation. When the plug is inserted into the spring jack to its normal distance,'the line circuit is completed to the connecting plug in the usual manner; but when it is desired to send a call signal to the substation from the exchange, the plug is 6o thrust entirely into the spring jack, whereby the extra contact piece upon the plug, Ior the i calling contact, is forced into contact with the line spring, thus connecting the source of calling current with the line.

To enable the operator to communicate with a subscriber at any substation or with either or both of two connected subscribers, I have devised means as followsz-One ofthe connecting plugs is provided with a metallic 7o heel piece connected with the tiporline contact piece of the plug, which rests in a metallic'socket when the plug is idle, the socket forming one terminal of the operators telephone set, the other terminal of the telephone being connected to earth or to a common return wire from the different substations. That plug which is not provided with a socket is employed in answering a call from a substation, so that when the operator has inserted the 8o answering plug into the answeringjack ofa calling subscribers line, her telephone set is connected with the line through the metallic socket, and heel piece of the other plug of the pair. To enable the operator to communi- 8 5 cate with two subscribers in connection I employ a contact piece or tip connected with the operators telephone set by a flexible cord, the contact piece or tip being adapted to be applied to the heel piece of any other connect- 9o ing plug. Thus when the operator desires to communicate with either of two subscribers in connection, she applies this contact piecewhich I shall call the listening plug`-to the heel piece of either ofthe plugs employed 9 5 in completing the connection between the subscribers, whereby her telephone set is connected in a branch from the complete loop circuit-,including the two substations.

I further provide novel means for testing Ico sulation.

the spring jack of any line to determine whether the line is already in use at some other spring jack or not.

In abranch from the cord circuit to the operators telephone set I include a source of electricity, a retardation coil being interpolated in the branch between the source of electricity and the cord circuit to prevent the escape of telephonie current from one cord circuit to another, when several cord circuits are thus connected with a single battery and telephone set. The connecting plug is arranged to cross together the normally insulated test ring and the line spring of the spring jack into which it may be inserted, in the usual manner, thus connecting the test rings to earth. When a line having such a connecting plug inserted into one of its spring jacks is tested in the usual manner,-that is by applying the tip ot' one of the connecting plugs to'a test ring-the test batterybranched from the cord circuit finds circuit through the flexible cord to the tip of the connecting plug, thence to the test ring to which this tip is applied, thence over the line to earth, returning to earth at the exchange, thence through the operators telephone set to the other pole of the battery. A click or other response is thus produced in the operators telephone receiver which indicates to her that the line tested is in use,-that is that the test rings of the spring jacks of that line are connected to earth.

My invention is illustrated in the accompanying drawings.

Figure l of the drawings is a longitudinal central section of a connecting plug for use in my system, disclosing the construction of the plug. Fig. 2 is another longitudinal central section of the plug taken on the plane at a right angle to the first section. Fig. 3 is a diagram illustrating the circuit connections of my improved switch board system.

The plug depicted in Figs. l and 2 comprises a tip a adapted to engage with the line spring of the spring jack into which the plug may be inserted, a short sleeve b insulated from the tip a, and a shank or body c connected with or integral with the tip a. The shank c is constructed as a tube having an enlarged heel piece c. Contact piece b is also tubular throughout the greater portion ot' its length, but is provided with an enlarged contact portion Z9 at its projecting end, and with a solid portion b2 adapted to receive the terminal of .a -flexible conductor, as b5., the same being secured to the tube b by a small binding screw b4. The shank c and the tube b are insulated from each other by insulating inaterial, as hard rubber, interposed between them. The tip a is provided with a stem a which extends axially through the tubular portion of the piece b and is screwed into a pin c2 which extends diametrically through the shank c, the stern o. and the pin c2 being also insulated from the piece b by suitable in- A binding screw c3 is provided on the inner surface of the shank c to receive another fiexible conductor, as c4. The tip a and the shank c are thus electrically and mechanically connected together, the piece b being securely held in its place, and being insulated from the other parts ofthe plug. The end of the tube b nearest the tip a', and the insulation interposed between that end of the tube and the tip, are beveled for a purpose which will presently be explained.

In Fig. 2 the plug is shown inserted into a spring jack. The slight bend in the extremity l of the line spring d of the spring jack normally rests in the position shown behind the tip a, but. by exerting a sufficient thrust7 upon the plug, the piece b may be forced under the line spring to connect with it; but as soon as the plug is again released, the pressure of the spring forces it from the spring jack until the line spring again rests in its normal position. The spring jack is provided with the usual test ring d which makes contact with the shank c ot` the plug and hence is connected with the line spring d as long as the plug is in the jack.

Referring now to Fig. 3, the apparatus at the substation is of the usual character. It comprises a calling generatore and signal bell e, and a telephone transmitter e2 and receiver e3 in two different branches from a conductor f, and a gravity switch e4 connected to another conductorf, and adapted to connect the signaling apparatus or the telephone apparatus alternately into circuit between the conductors f f according to the position of the switch. The conductor f is grounded at the substation. rlhe conductor or line f extends to the exchange, where it is connected through the line spring and back contact ot two spring jacks g and g upon two sections h h of a multiple switch board, and through an individual annunciator of usual construction, at the board h nearits spring jack g thereupon, thence Vto earth at the exchange.

The operator-s connecting outfit comprises two connecting plugs 7o 7c of the construction shown in Figs. 1 and 2. The tips or bodies of the plugs 7a k are connected by a flexible conductor Z. The contact pieces h b of the two plugs are connected by other flexible conductors which mayin practicebe included with the conductor l in a flexible cord in the usual manner. Acalling generator m, grounded at one pole, has its other pole connected with the conductor joining the pieces b b ot' the two plugs.

A metallic socket n is provided for the plug 7c,-the plug 7c being supposed to be the answering plug,-in which the plug 7.3 normally rests and with which the heel piece c of the plug makes electrical contact. The socket n is connected by a conductor with one terminal of the operators telephone set o, whose other terminal is connected with earth, and by a flexible conductor with a listening plug p.

A branch from the conductor Z extends through the retardation coil q, to one pole of ICO station 2 of the call.

the battery r, the other pole'of the battery being connected with the operators telephone set o. A clearingout annunciator s is iueluded in another branch connection from the conductor Zito earth.

I will now proceed to explain the operation of the system shown.

Suppose the subscriber at station 1 desires to communicate with the subscriber at station 2. The telephone receiver e3 being upon the switch `hook e4, the subscriber at station 1 rotates the handle of the generator e, thus sending current from the substation over the line f to the exchange, through the spring jacks g g thereat, thence through the annunciator t' to earth. The annunciator is thereby actuated, attracting the attention of the attendant operator at board h". The operator then inserts the answering plug 7c of the pair into the jack g of the calling line at her board. The circuitis thus continued from the substation to the line spring of spring jack g', thence to the tip a of the plug k, thence through the cord Z to the heel of plug 7c and thence,- the plug la being as not yetin use, and hence resting in its socket-to the socket fn, thence by a conductor to the telephone set o and to earth. VThe operator is enabled to receive the order from subscriber at station l, we will assume for connection with substation 2. The operator next proceeds to test the line to substation 2 to determine whether it is already in use, by the usual process of applying the tip of the remaining connecting plug la to the test ring d of the spring jack gs at her board. If the line tested were in use, current would iiow from the batteryr through the retardation coilq tothe conductor Z, thence to the tip of the plug le', to the test ring tested, thence to the shank of the plug by means of which the existing connection is made, to the line spring d of the spring jack into which the plug is inserted, thence over the line to earth, thence returning to earth at the exchange, through the operators telephone set o, to the other pole of the battery r. This iiow of current through the operator-s telephone set would produce a click in the telephone receiver at cach application of the testing plug to the spring jack tested. If, however, the line were not in use, no circuit would be completed when the plug k was applied to the test ring of the spring jack, and no response would be received by the operator. Having found the lines to station 2 not in use, the operator inserts the plug 7o fully into the spring jack g3, whereby the line spring of the jack is caused to enter upon the contact sleeve b of the plug, completing circuit from the calling generator m through the sleeve b to the line spring of the spring jack, over the telephone line to substation 2, where it traverses the Vsignal bell, and thence to ground, operating the signal bell and notifying the subscriber at The operator then allows the plug k to return to its normal position as shown in Fig. 2. The two substations are now connected through their lines to line springs of their respective spring jacks g and g3, which are united through the plugs 7i; and 7a and the conductor Z. The operators telephone set may be considered as being disconnected from the cord circuit, since no telephonie current can pass the retardation coil q. It at any time she desires to communicate with either of the subscribers, she applies the listening plugp to the heel piece c of that one of the plugs which is most convenient, whereby her telephone set o is connected in a bridge between the earth and the conductor Z joining the subscribers, and she is enabled to talk with the subscribers, or to hear their conversation. Vhen the subscribers have completed their conversation, one of them,we will assume for example that one at station l,- will replace his telephone upon the switch hook and rotate his generator e, thereby sending signaling current over the line to spring jack g' whence 'it finds circuit through the plug Za to the conductor Z, thence through the clearing-out annunciator s to earth. The shutter of the clearing-out annunciator is thus released indicating the signal for disconnection to the attendant operator.

Having thus described my invention, I claim as new and desire to secure by Letters Patentl. The combination with a connecting plug of a tip ct and a shank c electrically connected together and a sleeve or contact piece b insulated from the said shank and tip, substantially as described.

2.A The combination with a telephone line of a signal bell in circuit therein, a spring jack at the exchange having a line contact connected with one side of said telephone line, a connecting plug adapted to be placed in two different positions in the spring jack, said connecting plug having two contact pieces disposed to make contact one at a time with the line contact of the spring jack accoi-ding to the position of the plug therein, a source of calling current having one terminal connected with one of the contact pieces, the other terminal thereof being connected with the other side of the line circuit, and telephone apparatus connected with the remaining contact piece of the plug, substantially as described.

3. The combination with a telephone line extending from a substation to an exchange, of a signal bell at said substation included in the line circuit, said line including line springs and contacts of spring jack, and an individual aununciator at the exchange, each of said spring jacks being provided with a normally insulated test ring, all the test rings of the line being connected together, a connecting plug inserted into a spring jack ot' the line having a contact piece connecting with the line spring and the test ring of the spring jack and having another contact piece normally out of contact with both the line spring IIO and test ring but adapted to be moved to connect with the line spring, a source of calling current connected between the remaining side of the said line circuit and said extra contact piece upon the plug, and another connecting plug having similar contact pieces connected by a conductor with the rst mentioned plug, a metallic socket in which the said free plug rests and with which its line contact is connected, and the operators telephone set connected in a branch from the said socket to the other side of the said line circuit, substantially as described.

4. In combination, two connecting plugs each having three contact pieces, one contact being insulated from the remaining two, the remaining two being electrically connected, each of said plugs being adapted to be placed in either of two positions in a spring jack, the contact pieces of the plug being disposed to make contact one at a time with the line contact of the spring jack, the like contact pieces of the two plugs being connected by conductors, a grounded source of calling current connected with one of the said conductors, and a `grounded telephone set connected with the other of said conductors, substantially as described.

5. In combination, two connecting plugs each having three contact pieces, one contact being insulated from the remaining two, the remaining two being electrically connected, each of said plugs being adapted to be placed in either of two positions in aspring jack, the contact pieces of the plug being disposed to make contact one at a time with the line contact of the spring jack, the line contact pieces of the two plugs being connected by conductors, a grounded source of calling current connected to one of the contact pieces, a metallic socket adapted to receive one of the plugs when idle and to connect with the remaining contact piece, and a grounded telephone set connected with the said socket, substantially as described.

G. In combination, two connecting plugs each having three contact pieces, one contact being insulated from the remaining two, the remaining two being electrically connected,

each of said plugs being adapted to be placed in either of two positions in a springjack, the contact pieces of the plug being disposed to make contact one at a time with the line contact of the spring jack, the line contact pieces of the two plugs being connected by conductors, a grounded source of calling current connected with one of the contact pieces of the plug, a metallic socket adapted to receive one of the plugs when idle and to connect with the remaining contact piece thereof, a listening plug attached by a iiexible conductor to the said socket, and a grounded telephone set also connected with the same socket, substantially as described.

7. In combination, two connecting plugs having contacts adapted to connect with the line contacts of a spring jack, a metallic socket adapted to receive one of the plugs when idle and to connect with its line contact piece, a branch extending from the conductor joining the line contacts of the two plugs to the said socket, and including a source of electricity, and a telephone set grounded at one terminal having its remaining terminal connected with the said branch between the said source of electricity and the socket, substantially as described.

8. In combination, two connecting plugs having contacts adapted to connect with the line contacts of a springjack, a metallic socket adapted to receive one of the plugs when idle and to connect with its line contact, a branch extending from the'conductor joining the line contacts of the two plugs to the said socket,

Yand including a source of electricity, and a retardation coil included between said source of electricity and the said cord circuit, and a telephone set grounded at one terminal having its remaining terminal connected with the said branch between the said source of electricity and the socket, substantially as described.

In witness whereof I hereunto subscribe my name this 10th day of March, A. D. 1892.

CHARLES E. SGRIBNER. Witnesses.

M. J. TALLETT, GEORGE MoMAHoN. 

